SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c5e81137bd07fec0a20979f654c47d4dc20fa0b09bc10058023b10c1af70c5ff' 
  AND token = 'Cw5XXBUbac9DiShuHXN+Y7kxRbZJyNKysWD+wvsW7ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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