SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c251db063476a69380a34e2a252c8624eaf6e60076fe5725516ee1d3be6b9e' 
  AND token = '+eL7hwrb/NM+zBUflpiFbaEpivUdwcAiHovvS13Oxv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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