SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c97aa211cad054eafd5bc9d8753520f2d2efab5129edd807069cd4e5e61fbb9' 
  AND token = 'IVfqVg7fp8+KKMAlyukk2Vqro1OQbLPE1tpt46oHzck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}