SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '561dddafa18c38e69c22069b9397d16a8319849d86b61d69e053365608319546' 
  AND token = 'aWB5DscMulGXzgNAt4hzAEt1m+i6EVel2iYf40j2sIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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