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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1b1b4bde8aa3f32fface9c09d6a76f788a39de643421196fdb9984673eb0b12' 
  AND token = 'EE9ubp4bnpCVa+ZpPMzLt+RS/y66lWboAP9Mkojroh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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