SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '746628c52270cb7e77e3aadb3eca972fb020855a38893fa20807f5cdfaba32d8' 
  AND token = 'YeGHvuASYLi8Sw8n20DFcl4hX/KezCIs1yz3w+UUyp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}