SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3049b03e7b46377d9193fba42f1f04bf8af88db2e305a12c8a8cfb8009f24f5' 
  AND token = '0n7vPCvlvoQwQaQ4hqGqcDZKsyFQef5hP+Jl1RBlzro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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