SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4c4505d00f793ac3d87969f29d1e2c8b137764edb6083d3bb6dafdf2e076ecb' 
  AND token = 'zUzkaLVlmixwmkfJVohgbMfVPHp4X1kN58fr8kvxCWQ=' 
  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"
    }
  }
}