SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b3e9ff845f8807e2c01475632eb04fd8fb02b8921547e0b336028cb3c568f9' 
  AND token = 'jEdGFOpMa4OMdfgEGA+poMMjAEJsgjP8bvR6FPvzzSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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