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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd70a83d1bf10624a0980eeb9a30270eb2175eb8928b9573c813dab5cb935c38' 
  AND token = 'MMwViJdTLsNzLCOxSQqKNIV0naA+Qomnf0s2q31iqhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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