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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c234994ad3dc62eb0464596d55cb0eb6e2950cf9002d2d020f38f1ad8a0b0851' 
  AND token = 'MFeWzxMLnenfr9ZWfwkfpY6hW9GGLOEn/c0QHb6xbbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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